Rear Main Seal Replacement. Rope to Rubber
#1
Rear Main Seal Replacement. Rope to Rubber
I seen a few threads on this with no clear answer. Has any one on this forum use the Fel-Pro BS-6141 (292 Ford) rear main seal on SBO. I have 403 and would like to run the rubber but the direction and opinions I have read make it unclear if it is a good swap or not. If it is it will save time on tare down and cost for extra timing chain gasket set. I do not see how the Rope seal can be installed with out pulling the crank out of the block. Any body that has done this I would like to know how the Rubber worked out. I don't want to do it again, but If I can get out of a tare down and save time with a better seal this is what I want to do.
#3
main seal
Okay, So I have been told to shave all the rubber off the inside that makes contact with the crank. Is there anything else other than the lip going toward the inside of the motor not the flywheel? This should be easy to change with the crank in as well correct? I have already loosened the main caps and raised the crank about a 1/2".
#4
Interesting. I would like to know the procedure here too as I am in the process of doing the gaskets on my 350 and would like to use the rubber seals instead of the rope ones. Any and all info appreciated!
Dennis
Dennis
#7
As far as being easy, well... It's a PIA, but you should have no real problem sliding the seal in and around in a circle if you're patient.
- Eric
#8
Jones 1978:
I haven't done this yet but getting educated for my upcoming engine build. Thanks for posting about the Ford seal for Olds small blocks.
#9
#10
Eric:
I watched a You-tube video showing Travatto building a small block Olds motor (I think it was a diesel block). But the diesel blocks have BBO sized main bearing so you're right about the Ford 460 seal for 455 Olds motors. I'm getting ready to build a 375 small block stroker and want to use a better seal than the rope seal that comes in the gasket set. Maybe you don't have to trim the rubber off the backside of the Ford 292 seal to get it to fit in a small block?
I watched a You-tube video showing Travatto building a small block Olds motor (I think it was a diesel block). But the diesel blocks have BBO sized main bearing so you're right about the Ford 460 seal for 455 Olds motors. I'm getting ready to build a 375 small block stroker and want to use a better seal than the rope seal that comes in the gasket set. Maybe you don't have to trim the rubber off the backside of the Ford 292 seal to get it to fit in a small block?
#11
Exactly.
I try to avoid making blanket pronouncements when I haven't done a particular thing a number of times myself, but I can say that I didn't have to trim mine.
- Eric
- Eric
#12
Trimming the seal as described sounds like a bad idea.
I've installed the Ford small block seal AS-IS in a couple of 330's with no problems.
It went in like it was made for the Olds engine.
One thing I'd read to do, that I didn't do, but it makes sense,
is the grooved, knurled surface on the crank
where the seal makes contact should be smoothed with emery cloth.
Apparently the knurled surface somehow seated the rope-type seal, but,
there is concern about the knurl wearing the Ford seal prematurely which makes sense.
Also, you probably already know this but, instead of installing the seal halves with the ends
flush with the mating surfaces on the block and bearing cap, leave one end of each half
sticking up so that the ends of the seal halves meet in the block and cap rather than at the mating surface.
Also, use a small dab of silicone on the ends of the seal halves to seal the ends together.
I've installed the Ford small block seal AS-IS in a couple of 330's with no problems.
It went in like it was made for the Olds engine.
One thing I'd read to do, that I didn't do, but it makes sense,
is the grooved, knurled surface on the crank
where the seal makes contact should be smoothed with emery cloth.
Apparently the knurled surface somehow seated the rope-type seal, but,
there is concern about the knurl wearing the Ford seal prematurely which makes sense.
Also, you probably already know this but, instead of installing the seal halves with the ends
flush with the mating surfaces on the block and bearing cap, leave one end of each half
sticking up so that the ends of the seal halves meet in the block and cap rather than at the mating surface.
Also, use a small dab of silicone on the ends of the seal halves to seal the ends together.
#14
I don't claim to have the "right" answer, but I have not (personally) seen any documentation of anyone who did not smooth the serrated surface and subsequently had a sealing problem.
- Eric
#15
... But, there are some who have not done this (such as yours truly), who have had no problems.
I don't claim to have the "right" answer, but I have not (personally) seen any documentation of anyone who did not smooth the serrated surface and subsequently had a sealing problem.
- Eric
I don't claim to have the "right" answer, but I have not (personally) seen any documentation of anyone who did not smooth the serrated surface and subsequently had a sealing problem.
- Eric
#16
You can of course just install the crank without it polished and it will probably be fine...if you you make sure its smooth as a babys butt you will be certain it will be fine...provided its round and seal is installed correctly
#18
Installing a BS-6141 (292 ford) rubber main seal in a SBO
Ok so I didn't get any straight answers out of any reads or videos, or people so here is what I have done. This is with the motor out of the car. I removed all the main caps and pried up on the rear of the crank where the flywheel goes. ( I did not remove the front of the motor so the crank couldn't be removed.) Remove the Rope seal with wire or something flexible and stiff. Now To install the FEL-PRO BS-6141 Take it out of the package and trim the outer spine of the seal ( MOTOR SIDE NOT CRANK SIDE) use a pry bar to lift the crank out of the motor as far as you can and after coating the seal with oil and facing the lip of the gasket toward the front of the motor work it in to the block under the crank. They say to off set the seal 3/8" on the block and cap... I have it installed and the crank moves free. Re-install the Main caps and work front to back to set crank back in block. Torque to spec and reassemble motor. Hope this clears up the unanswered questions on using the Ford 292 rubber seal to replace the rope seal.
Last edited by jones1978; August 8th, 2015 at 05:57 PM.
#21
rubber rear main seal for SBO
I did use Black RVT on the ends of the main seal where they come together. I did not use any on the inside of the motor or main cap. As far as the unanswered questions, I didn't check the post before I wrote my input. I think this will benefit a lot of people who have been looking for the whole answer and not just what seal to use and that it worked well. I could not install the seal with the crank in. The rubber spline was catching on the block. after shaving the spine off it still had to be worked into the block. I believe that it may not have to be trimmed if the crank is out of the block. I will see how that works on a 455 I will be building in the future. Thanks for all the input.
#22
I installed one with the engine out and the crank and rods in place, with the main caps loosened, with the crank less than a quarter inch raised, by pulling the rope seal out in pieces with a pair of very long needlenose pliers, lubing the channel, and simply feeding the seal into the channel by firmly rotating it into position, without trimming or modifying it in any way.
Once the seal seemed to be in position, square with the machined surface of the block, I pressed on both edges to be sure it was seated, cleaned the end faces well, then pushed it a few degrees to get one end to poke up, as recommended, applied silicone sealant, and reassembled.
As with my comment above, I'm not saying anything is right or wrong, but that was my experience.
- Eric
Once the seal seemed to be in position, square with the machined surface of the block, I pressed on both edges to be sure it was seated, cleaned the end faces well, then pushed it a few degrees to get one end to poke up, as recommended, applied silicone sealant, and reassembled.
As with my comment above, I'm not saying anything is right or wrong, but that was my experience.
- Eric
#23
rear main
I tried to install mine without trimming and it hung up on the block. I tend to rush things though. I don't see that 1/32 of lip being an issue with clearance. I believe it would work with it attached as well. I would do it again. I tend to ask a lot of questions until I am comfortable doing something. If it does not seal it is a major job to redo. I would hate to think I have to pull the whole motor again to install a 15.00 seal. I think I would douse it with gas and torch it if that were the case.....
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